Napoleon’s March to Moscow

Why we love it

A new take on an old classic, the Minard map of Napoleon’s tragic march to Moscow is reimagined as a 3D space-time cube. We love the interactive pan, rotate, and zoom options. Time is on the vertical axis, anchored to a basemap that shows the location of cities. The slope of the line tells us how fast the troops were moving and vertical lines are periods of no movement. Troop movement dwindles downward as soldiers fall victim to injury, illness and harsh weather.

Why it works

New technology can make for new insight and give mapmakers a chance to present data in a rich new format. The Minard map showed a complex interplay of army size, location, direction, varying temperatures and a devastating loss of French troops. This interactive 3D version shows all that, plus time spent in each location so we can really see how Napoleon’s decisions turned disastrous, even deadly.

Important steps

Vary the thickness to represent movement

Represent troop flow by varying the thickness of the linear feature that represents movement.

Build from segment to segment

In 3D, the lines are represented by cylinders, split into different cylindrical segments. Each of the line segments is height-enabled with a different z value for the start and end of the line (based on the real dates), and so the 3D line is built from segment to segment.

Reflect the maps original colours

The cylinders are coloured according to the original map with tan representing the advance, black the retreat. Grey vertical cylinders represent stationary periods.

Create different heights

The basemap, cities, vertical lines, and other map detail use extrusion to create 3D objects and have different base heights set so they are at different heights in the space-time cube.

Requirements

Data and software

3D space-time cubes are ideal for linear features and not as good for polygonal data. If you put too much data into the 3D space you create overlap and visual clutter. Software used: ArcGIS Desktop, Esri CityEngine, ArcGIS Online.

Analysis

With the analysis already done for the original map, the task that remains is to scale the thickness and slope of troop movement so it looks pleasing.

Time

Most of the work is in preparing data and ensuring the z values are properly attributed to the lines. Changing base heights and extruding features for the layers takes roughly three hours. Publishing as a web scene takes one hour.

Tips and tricks

Measure more than elevation

Instead of using elevation to add height to your map in a web scene, encode other variables such as time or perhaps an uncertainty value to create a time or data cube.

Create old things in new ways

Rebuilding or reimagining a classic, historical map is a great way to explore how to replicate old cartographic techniques or create new ways of seeing.